The prevalence of migraine is said to be approximately 6% of the male population and 18% of the female population. Treatment for many patients having the occasional migraine usually involves simple analgesics, non-steroidal anti-inflammatory agents, or specific agents such as ergotamines or triptans. Approximately 10% of migraine sufferers have three or more attacks per month and warrant prophylactic treatment. Preventative agents such as beta-blockers, tricyclic antidepressants and divalproex sodium can reduce but not eliminate migraine attacks in some patients. Thus, there remains a need for migraine specific medications such as sumatriptan. In the remaining population of migraine sufferers, and in those with intolerable side-effects from available drugs, there is a lack of conventional pharmaceutical preparations that exhibit therapeutic effect, without severe side-effects.
Droperidol presently is marketed by Taylor Pharmaceuticals under the trademark Inapsine, as an injectable formulation used in anesthesia for preoperative surgery. It has never been approved for use in the treatment or management of migraine attacks.
A limited, uncontrolled, non-blinded, use of droperidol lactate (2.5 mg/ml droperidol) to treat migraine attacks was attempted and the results published in Headache, April 1996, p.280. In that publication it was reported that 20 patients received from 2.5 to 7.5 mg droperidol intravenously, in increments of 2.5 mg every 30 minutes until the patient was headache free or until a total of three doses had been administered. The mean dose was 5.6 mg. All of the patients received prior treatment with migraine therapies. Eighteen of the patients reported to be headache-free by the last dose. Although the article reports on apparently encouraging results in treating migraine attacks with droperidol, no definitive conclusions can be reached from the results reported in that article as the number of patients treated was small, the study was not blinded, all patients received other agents to treat the migraine episode prior to receiving droperidol, and there was no placebo control. Also, there was no attempt to repeat the results with the patients. Further, no attempt was made to prolong therapy beyond the initial treatment to a headache-free state and most patients had continuing symptoms to some degree within 24 hours after the last droperidol treatment.
Additionally, the aforementioned study and article only used intravenous droperidol. Others also have used intramuscular droperidol in uncontrolled, open studies for treatment of migraine of varying dose levels of droperidol. The use of droperidol by injection raises several issues, not the least of which is inconvenience to the patient, caused by the need to have the droperidol administered by a health care professional.
Accordingly, a need exists for a means to treat patients who suffer from, or are at risk of, a migraine episode, that does not require the use of injections of droperidol.